Assessment and significance of phytoplankton species composition within Chesapeake Bay and Virginia tributaries through a long-term monitoring program

Phytoplankton and water quality long term trends are presented from a 20-year monitoring program of Chesapeake Bay and several of its major tributaries. Increasing phytoplankton biomass and abundance are ongoing within this estuarine complex, with diatoms the dominant component, along with chlorophytes and cyanobacteria as sub-dominant contributors in the tidal freshwater and oligohaline regions. Diatoms, dinoflagellates, and cryptomonads are among the major flora downstream in the tributaries and within the Chesapeake Bay. Water quality conditions within the three tributaries have remained rather stable over this time period; while there are long term trends of reduced nutrients, increasing bottom oxygen, and decreasing water clarity for the lower Chesapeake Bay. Of note is an increasing trend of cyanobacteria biomass at 12 of the 13 stations monitored at tributary and Chesapeake Bay stations, plus the presence of 37 potentially harmful taxa reported for these waters. However, the overall status of the phytoplankton populations is presently favorable, in that it is mainly represented and dominated by taxa suitable as a major food and oxygen source within this ecosystem. Although potentially harmful taxa are present, they have not at this time exerted profound impact to the region, or replaced the diatom populations in overall dominance.     

Organic speciation of atmospheric particles in Alvão Natural Park (Portugal)

PM₁₀ continental rural background aerosols were collected during a summer field campaign (August–September 2006) at Lamas de Ôlo in the upper zone of the Alvão Natural Park, a mountain region of northern Portugal. In addition to the determination of the carbonaceous content by a thermal–optical method, the organic speciation of aerosols was performed by gas chromatography–mass spectrometry in an effort to evaluate photo-oxidation products of biogenic volatile organic compounds and other markers for source characterization. The detailed analysis revealed relatively high concentrations of polyols and short-chain dicarboxylic, tricarboxylic, hydroxycarboxylic, and oxocarboxylic acids, many of which are thought to be indicators of secondary aerosol formation, accounting for about 70% of global chromatographically resolved mass. Major photo-oxidation products of α- and β-pinene have been detected. The tracers for the photo-oxidation of isoprene comprise two diastereoisomeric 2-methyltetrols, C₅-alkene triols, and 2-methylglyceric acid, which have only recently been elucidated. In addition, the occurrence of levoglucosan and other biomass combustion tracers indicates that the site was affected by wildfires. This source contributed to more than 80% of the organic carbon mass during a period of strong forest fire influence.     

Reusing fly ash in glass fibre reinforced cement: a new generation of high-quality GRC composites

New composite materials based on an alkali-resistant glass-fibre reinforced cement (AR-GRC) system are being developed by using fly ash (FA) produced at coal thermoelectric power plants, and fluid catalytic cracking catalyst residue (FC3R) from the petrol industry as cement replacement materials. These wastes are reactive from the pozzolanic viewpoint, and modify the nature and the microstructure of the cement matrix when a part of the Portland cement is replaced in the formulation of GRC. Several microstructural and mechanical aspects are being studied for AR-GRC systems. The behaviour of composites exposed to ageing shows that the pozzolanic activity of the ground FA added in high amounts and its mixture with the FC3R increase the flexural strength and no evidences of strength decay are observed. Additionally, the fibres due to the high alkalinity of the cementing matrix can be deteriorated. Fibres in the control (only Portland cement) and FC3R containing composites were attacked, whereas composites with FA and their mixture with FC3R show that the fibres have not been attacked, due to the pozzolanic activity of replacing materials that reduce the calcium hydroxide content in the cementing matrix.     

Management of MSW in Spain and recovery of packaging steel scrap

Packaging steel is more advantageously recovered and recycled than other packaging material due to its magnetic properties. The steel used for packaging is of high quality, and post-consumer waste therefore produces high-grade ferrous scrap. Recycling is thus an important issue for reducing raw material consumption, including iron ore, coal and energy. Household refuse management consists of collection/disposal, transport, and processing and treatment - incineration and composting being the most widely used methods in Spain. Total Spanish MSW production exceeds 21 million tons per year, of which 28.1% and 6.2% are treated in compost and incineration plants, respectively. This paper presents a comprehensive study of incineration and compost plants in Spain, including a review of the different processes and technologies employed and the characteristics and quality of the recovered ferrous scrap. Of the total amount of packaging steel scrap recovered from MSW, 38% comes from compost plants and 14% from incineration plants. Ferrous scrap from incineration plants presents a high degree of chemical alteration as a consequence of the thermal process to which the MSW is subjected, particularly the conditions in which the slag is cooled, and accordingly its quality diminishes. Fragmentation and magnetic separation processes produce an enhancement of the scrap quality. Ferrous scrap from compost plants has a high tin content, which negatively affects its recycling. Cleaning and detinning processes are required prior to recycling.     

Reevaluation of ENCORE: support for the eutrophication threshold model for coral reefs

The results from the multimillion dollar Enrichment of Nutrients on Coral Reefs Experiment (ENCORE) on One Tree Island Reef (OTIR) suggest that increased nutrient loads to coral reefs will have little or no effect on the algal growth rates and, hence, on the associated effects that increased algal growth might have on the functioning and stability of coral reefs. However, a comparison of the concentrations of nutrients within the OTIR lagoon with the proposed nutrient threshold concentrations (NTC) for coral reefs suggests that all sites, including the control sites, were saturated with nutrients during ENCORE, and, hence, one would not expect to get any differences between treatments in the algal-growth related measurements. Thus, ENCORE results provide strong support for the proposed NTCs and support the ecological principle that algal productivity and, consequently, the functioning of coral reefs are sensitive to small changes in the background concentrations of nutrients. The principal conclusion of ENCORE, namely that the addition of nutrients did not cause the "pristine" OTIR to convert from coral communities to algal dominated reefs, is contrary to the fact that there was prolific macroalgal growth on the walls and crests of the experimental microatolls by the end of ENCORE.     

Estrogenic activity removal of 17beta-estradiol by ozonation and identification of by-products

This work investigated the degradation of a natural estrogen (17beta-estradiol) and the removal of estrogenic activity by the ozonation process in three different pHs (3, 7 and 11). A recombinant yeast assay (YES assay) was employed to determine estrogenic activity of the ozonized samples and of the by-products formed during the ozonation. Ozonation was very efficient for the removal of 17beta-estradiol in aqueous solutions. High removals (>99%) were achieved with low ozone dosages in the three different pHs. Several by-products were formed during the ozonation of 17beta-estradiol. However, only a few compounds could be identified and confirmed. Different by-products are formed at different pHs, which is probably due to different chemical pathways and different oxidants (O(3) and OH radical). The by-products formed at pH 11 were 10epsilon-17beta-dihydroxy-1, 4-estradieno-3-one (DEO) and 2-hydroxyestradiol, which were not formed in pH 3. Only testosterone could be observed in pH 3, whereas at pH 7 all three by-products were found. At pH 7 and 11 the applied ozone dosages were not enough to remove all the estrogenicity from samples, even though the 17beta-estradiol residual concentration for these two pHs was lower than at pH 3. Higher estrogenicity was detected at pH 11. An explanation to this fact may be that oxidation via OH radical forms more by-products with estrogenic activity. Probably, the formation of 2-hydroxyestradiol at pHs 7 and 11 is contributing to the residual estrogenicity of samples ozonized at these pHs. In this work, complete removal of estrogenic activity was only obtained at pH 3.     

Gravitational infusion of ethylenediurea (EDU) into trunks protected adult European ash trees (Fraxinus excelsior L.) from foliar ozone injury

Adult ash trees (Fraxinus excelsior L.), known to be sensitive or insensitive to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion on six occasions at 21-day intervals in summer 2005 at Turin, Italy. At the end of the season, foliar ozone injury on EDU-treated trees was not complete, but was greatly and significantly reduced when compared to results from trees infused with water. Significant symptom reduction occurred at any crown level in the treated trees suggesting that EDU protected whole crowns. Gravitational infusion of EDU resulted in protection from ozone injury for ozone-sensitive ash trees. The amount of EDU needed to provide protection is assumed to be in the range 13-26 mg m(-2) leaf.     

Lichen and moss bags as monitoring devices in urban areas. Part II: trace element content in living and dead biomonitors and comparison with synthetic materials

Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality.     

Meta-analysis of the relative sensitivity of semi-natural vegetation species to ozone

This study identified 83 species from existing publications suitable for inclusion in a database of sensitivity of species to ozone (OZOVEG database). An index, the relative sensitivity to ozone, was calculated for each species based on changes in biomass in order to test for species traits associated with ozone sensitivity. Meta-analysis of the ozone sensitivity data showed a wide inter-specific range in response to ozone. Some relationships in comparison to plant physiological and ecological characteristics were identified. Plants of the therophyte lifeform were particularly sensitive to ozone. Species with higher mature leaf N concentration were more sensitive to ozone than those with lower leaf N concentration. Some relationships between relative sensitivity to ozone and Ellenberg habitat requirements were also identified. In contrast, no relationships between relative sensitivity to ozone and mature leaf P concentration, Grime's CSR strategy, leaf longevity, flowering season, stomatal density and maximum altitude were found. The relative sensitivity of species and relationships with plant characteristics identified in this study could be used to predict sensitivity to ozone of untested species and communities.     

Estimates of ambient background concentrations of trace metals in soils for risk assessment

Site-specific or soil type-specific ambient background concentrations (ABCs) of trace metals in soils are needed for risk assessment. We investigated three different methods for estimating ABCs in soils using a dataset of 5691 soil samples from England and Wales. The concentrations of Co, Cr and Ni were strongly associated with Al and Fe, and multiple regressions explained 62-85% of their variation, and Al and Fe can therefore be used to predict ABCs for these metals. Soil texture had a major influence on the concentrations of Cd, Co, Cr, Cu, Ni and Zn, and the medians were 3-5 fold higher in clayey than in sandy soils. This was used to predict texture-specific ABCs. Lead concentration was higher in acidic peaty soils than in other soils. A probability graph method was used to estimate ABC for Pb in a population of relatively uncontaminated soils. Potential applications of ABCs are discussed.